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Old May 26, 2009, 10:53 PM   #1
kiwi56
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Cock on opening vs cock on closing

A few years ago I was getting a gunsmith to do some work on my Mauser 96 sporter. After discussing the required work he said to me "I suppose you want it converted to cock on opening", my reply was "why, can you show me any advantage in it for a hunting rifle" he responded with most people want them that way but like me he thought it was extra work for no apparent reason. Does anyone else see something that we are missing? I would be interested to hear other peoples views on the subject.
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Old May 26, 2009, 11:04 PM   #2
StiveC2007
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I agree with you whats the point either way the bolt has to be cycled. so whats the benefit if the bolt cocks on open or close.
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Old May 26, 2009, 11:08 PM   #3
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Somebody will come along with some reason but I don't see any advantage.
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Old May 26, 2009, 11:22 PM   #4
nimbleVagrant
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A mauser 96 isn't already a cock-on-opening design? I've never operated a 96 so I don't actually know. the arguable advantage to a cock-on-close design is faster bolt cycling as seen on the Lee-Enfields.

did a quick bit of research: it appears the 96 is a COO and the reason many people convert them is to improve the feeling of the bullet seating. And the lock time may also improve with this modification.

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Old May 26, 2009, 11:50 PM   #5
Wrothgar
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Only rifle I've seen cock on closing is an enfield. My rifles (98K, Mosin Nagant, Winchester 22) all cock on opening.
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Old May 26, 2009, 11:53 PM   #6
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the only advantage is that....

all effort in cock on closing, is that all force is applied for extraction only,.

This was the primary thinking of British forces using the Lee-Enfield.

Have both types never noticed a difference.
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Old May 27, 2009, 12:33 AM   #7
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I think cock on closing rifles cycle much faster. Honestly, I wish there were more contemporary designs that cocked on closing.
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Old May 27, 2009, 12:39 AM   #8
Mike Irwin
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Japanese Arisakas, Lee Enfields, British Pattern 14/American Model 1917 Enfields, are the most commonly encountered cock on closing guns.

As was noted, the thought was that with a cock on closing gun all opening effort was going towards initial extraction of the case from the chamber. That was probably a bigger consideration in the days when the manufacture of cartridge brass was still kind of iffy.

With the original Lee Metford design it was also probably a good thing since the original .303 British cartridge was loaded with black powder, which could quickly foul a chamber and lead to sticky extraction.

In the case of the Lee Enfield, it also contributed to greater overall speed in operating the bolt, which allowed British regular army troops at the Battle of Mons in WW I to fool their German counterparts into thinking that they were facing massed machine guns when there actually were no British machine guns in operation at that point in the battle.
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Old May 27, 2009, 01:04 AM   #9
Three44s
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I recently bought a M1917 Enfield ....... I own many cock on opening bolt guns ...... this P17 is my first COC .........

I like it.

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Old May 27, 2009, 01:16 AM   #10
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Most of my bolt guns are cock on close.

As pointed out, you're not working to cock the gun during the bolt-opening phase which means you can more easily extract sticky cases. As pointed out, that's not much of an issue these days--if it is you've probably got bigger problems than trying to get the bolt open.

I've seen some folks claim that the cock-on-open conversion to the Model 96Mausers weakens the cocking piece. I haven't had a 96 bolt apart in awhile so I can't tell you why that would be.
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Old May 27, 2009, 01:53 AM   #11
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Mike has it covered ... saves me the usual 3 paragraphs; I prefer my Enfield actions over any other type I have encountered - the design makes perfect sense to me and is certainly preferable where fast case extraction is concerned. I own K98's and Mosin Nagant rifles as well and I can't cycle any of them as fast as the Enfield.

For me the cock on closing design is superb and my own personal preference given a choice. The principle is very clever and is something the Japanese must have recognised from their own analysis of tools in carpentry - a perfect example is the Japanese Pull Saw! I come from a long line of Cabinet Makers ... and if you've had any experience of carpentry and furniture making then this will make your life very easy indeed.

The Japanese realised that when using a standard saw when putting forward motion effort into cutting that this was far more fatiguing than withdrawal of the blade. As a result of this realization, the Japanese created the Pull Saw which situated the angle of the blades such that they worked on the pulling motion of the arm not the pushing. This different approach made cutting far less tiring and fatiguing and made the work easier as well as more accurate too. You can cut through an object with a pull saw in half the time it takes with a standard toothed blade and finish with far less fatigue.

The exact same principle applies to the British concept of cock on close ... the solider in battle has little work to do to extract the case and instead all efforts are focused on ramming the new round home. The British soldiers ability to cycle the bolt and get shots down range are increased significantly by using this design ... less fatigue means faster cycle rate and in a muddy trench cock on close means more reliable extraction and less chance of jammed bolts and cases. The Japanese understood this and it's interesting to note that the Arisaka Type 99 cal conforms closely to British .303 specs; ballistically they are both very similar.

Great minds think alike. ( And for those who haven't tried it ... next time you have heavy cutting to do, try a Pull Saw. )

Best, Tiki.
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Old May 27, 2009, 05:06 AM   #12
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Bolt opening closing

I know that several companies like Dayton Traister actually made kits to convert the 96 or Swedish model Mauser from cock on closing to cock on openining but I still cant see any advantage in the conversion. What I dont like about the cock on opening is the fact that once you open the action the firing pin spring is immediately under compression. I must admit I don't ever use a safety on a rifle and before people start saying I am irresponsible let me tell you the safety I use is an open action with an empty chamber. Even when shooting deer I have never had a problem with having to chamber a round and then fire, if for some reason the shot is not on I simply put the round back into the magazine.
The old Lee Enfield used to be good for this as you when close to game you could half close the bolt and use the friction of the safety to hold the bolt in a half open position with a cartridge halfway into the chamber.
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Old May 27, 2009, 05:09 AM   #13
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As long as

It's cocked when you need to fire it

And don't go off before you're ready
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Old May 27, 2009, 05:42 AM   #14
Tikirocker
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Quote:
The old Lee Enfield used to be good for this as you when close to game you could half close the bolt and use the friction of the safety to hold the bolt in a half open position with a cartridge halfway into the chamber.

I'll go you one better Kiwi ... Commonwealth soldiers used to close the bolt on a single round (which was the extra up the pipe) - with the mag already loaded with ten - and by pulling back on the cocking piece one click you could half cock the rifle and leave it there with the bolt closed. If you needed to fire quickly you only needed to pull the cocking piece back the final notch and you could fire right away.

I have used this same technique when hunting ... works a charm.

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Old May 27, 2009, 07:13 AM   #15
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The only problem with that, Tiki, is that the Japanese never adopted a bolt handle design that would allow operation of their rifles with anything even remotely resembling the speed, facility, or ease of the Lee Enfield.

The only turned down bolts that were commonly seen in service were in later sniper rifles. Everything else had a straight bolt handle, and when bolt throw is roughly 90 degrees, any illusions of speed are shattered.
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Old May 27, 2009, 08:26 AM   #16
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Mike,

I concur ... the Japanese were understanding the principle from the perspective of positive extraction - they made up for a lack of speed by furnishing one of the strongest receivers ever made. This didn't make an ounce of difference in battle but it's a nice thing to have from an engineering standpoint.

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Old May 27, 2009, 01:53 PM   #17
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If you scope the thing, you may find that cock on opening is easier to use.

Pushing against a strong mainspring with a bent bolt handle and little clearance is a recipe for jamming your fingers.

All the cock on closing rifles that I can think of have enormous cocking pieces and a long striker fall. This may be an ignition advantage in the mud of Flanders and cold of Siberia. For most of us, this is a non consideration.

Most modern actions are cock on opening, these will be faster to operate than a M96.

If there was a way to prove it, I would love to race someone with a M96, while I stroke the bolt on my pre 64 M70. My bolt lift is so easy with that rifle. I know my rapid fire group would be tighter because I would not be losing my position pushing against the mainspring.

In terms of speed, while the Lee Enfield is extremely fast to dry fire, when I load cartridges in the thing, the frictional drag from the case head against the receiver wall slows my bolt manipulation to an effective speed lower than a M98.
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Old May 27, 2009, 02:49 PM   #18
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Cocking opening vs closing

One mod I did do to the 96 Mauser was to put in a higher power firing pin spring, This did reduce the lock time but required a bit more physical effort to close the bolt.
The rifle I have was a commercial Mauser based on the small ring 96 design made by Stiga in Sweden. These rifles appeared to be manufactured as a long action, mine was in 30-06 and I have seen several in both 30-06 and 270 Winchester as well as one that was obviously rebarrelled in 25-06. Thinking that this would be about the upper limit of pressure that a small ring Mauser action could take, I was surprised to read that some of these commercial 96 Mauser actions had been chambered for cartridges as large as the 7mm Remington Magnum and I thought that cartridge would have been better suited to the 98 Mauser.
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Old May 27, 2009, 03:34 PM   #19
James R. Burke
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Kiwi that is very good and safe. Myself and wife always go to our blinds and back empty. Now you got me thinking that would make it even more safe. No deer is worth a accident. Nothing but a good comment from me on that. Most rifles I dont thing it would matter if it cocked when closed as poitned out on the replys.
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Old May 27, 2009, 03:57 PM   #20
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I agree with SlamFire1 on this one. Although it's of no real concern, the cock on closing on my M96, sporterized by Kimber of Oregon and left in 6.5x55, is a much stiffer action than my CZ 550 in 6.5x55 and there is no comparison with any of my pre '64s or even my mod 70 Classics for that matter. Again, it's a nice enough rifle, but I'd supect changing it to cock on opening would make it seem smoother cycling, without the unusual extra force needed now to close.
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Old May 27, 2009, 06:23 PM   #21
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I suspect Paul Mauser had some reason to switch to cock on opening in 1898 otherwise all 98's would be cock on closing. One of the reason I have heard is that the firing pin extends out at full length to fire a round. In the event the bolt didn't get cocked as the bolt was closed the gun might fire before the lugs engaged. There were other causes, a bullet came out of the mag and hung up on some part of the receiver with the firing pin all the way out could also case the round to fire. I don't know any more than that, but cock on closing has been a dead issue pushing 100 years.
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Old May 27, 2009, 08:54 PM   #22
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"the frictional drag from the case head against the receiver wall slows my bolt manipulation to an effective speed lower than a M98."

You need to train more.

I'm FAR faster with a Lee Enfield than I am with either a Mauser or a Springfield.
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Old May 27, 2009, 08:56 PM   #23
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"I don't know any more than that, but cock on closing has been a dead issue pushing 100 years."

Just like the bolt action military rifle has been a dead issue for nearly as long, and yet here we are still talking about all of them on a regular basis.


There may also be another reason that we're overlooking for the cock on closing action -- ease of manufacture.

I'm pretty sure that the bolt is far simpler to manufacture on such a rifle, and that might have been a big consideration in the early days of mass producing these rifles.
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Old May 28, 2009, 02:26 AM   #24
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cocking

Mike Possibly the main reason we are still talking about it is that basically the design of the bolt action military and sporting rifles was probably perfected one hundred and ten years ago with the advent of the 1890's series Mausers. Sure the tolerances have become tighter and the machinery for manufacturing has become more accurate as well as stronger materials but in actual design of the rifles there have only been minor refinements in that time.
During the second world war the British armies accuracy requirement for a sniper rifle was for it to shoot 1 MOA, most sporting rifles these days are capable of that level of accuracy with a little work.
Back in WW2 each rifle was tested with a five shot group and occasionally one would deliver that amount of accuracy and would be put a side aside to be sent off to a gunsmith for strippng and a few accuracy improvements such as trigger job etc. If you like these rifles were a fluke of manufacturing where they suddenly got everything right but these days it is very different matter where a bolt rifle can be manufactured from day one to go sub MOA.

Last edited by kiwi56; May 28, 2009 at 02:38 AM.
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Old May 28, 2009, 10:01 AM   #25
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Trivia question for you...

Know who fitted most No. 4 Mk I(T) rifles for sniper duty?

Holland and Holland.

Supposedly a FEW were also fitted by Rigby, but I've never seen one.


And who needs a bolt action anyway when Arthur Savage perfected the lever action rifle in 1899?
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